These are the companies abandoning the U.S. to dodge taxes

It is a tax trick that has been around for years, but the pace of companies moving their headquarters overseas to lower their tax rate has sped up in the last decade.

American firms have moved overseas at a time when a growing number of countries have reduced tax rates. These "inversions" have been taking place as Congress remains at odds over lowering the corporate tax rate of 35 percent, one of the highest rates in the world.

The Obama administration and many lawmakers agree that tax inversions, shelters and all other maner of tax alchemy are an outgrowth of a broken corporate tax code. Yet they say the failings of the tax system are no excuse for companies not to pay their fair share.

Democrats on the House Ways and Means Committee recently posted a nifty chart of companies that have inverted to lower their tax bills since 1983. We took the information a step further by adding where the companies moved their headquarters, and when available how much revenue they earned last year.

Some companies were acquired by larger rivals. Others are simply no longer in business. For the better part of two decades, Caribbean countries such as Bermuda and the Cayman Islands were hot spots for reincorporation. That started to change in 2004 when Congress said American companies could relocate overseas if foreign shareholders owned 20 percent of their stock. Europe became an natural choice because many companies had an established presence there and tax rates were generally lower than the United States, especially in Ireland and, more recently, Britain.

Now Democratic lawmakers want to up that stock threshold to 50 percent to make it harder for firms to hightail it out of the country. That push to change tax policy is gaining momentum in Washington and may factor into midterm congressional elections. In the meantime, here is a look at some of the firms that have inverted. The list is far from exhaustive, but offers a glimpse into a practice that some say is robbing the U.S. of billions of dollars in tax revenue.

Danielle Douglas-GabrielDanielle Douglas-Gabriel covers the economics of education, writing about the financial lives of students, from when they take out student debt through their experiences in the job market. Before that, she wrote about the banking industry. Follow